If a substance is dissolved in water or heated ， it may （）a gas.
A、giveinto
B、giveover
C、giveoff
D、giveaway
_____, he can now only watch it on TV at home.
A、Obtainingnotaticketforthematch
B、Notobtainingaticketforthematch
C、Nothavingobtainedaticketforthematch
D、Notobtainedaticketforthematch
Modern（）perhapscausesmoreproblemsthanitsolves.
A、technique
B、technology
C、tactics
D、tendency
_____time,he’llmakeafirst-classtennisplayer.
A、Having
B、Given
C、Giving
D、Had
A、Whynottocallon
B、Whydon'tcallon
C、Whynottocallingon
D、Whynotcallon